The invention provides a method for improving corrosion resistance of a bipolar plate of a fuel cell, comprising the following steps: firstly, preparing a bipolar plate prefabricated part of a stainless steel material, and then, depositing a C-Ni coating layer on the surface of the prefabricated part. According to the method in the invention, a plasma deposition technology is adopted, and the C-Nicoating layer deposited on the surface of the stainless steel can effectively improve the corrosion resistance and the electrical conductivity of the bipolar plate. The C-Ni coating layer is a hydrophobic material which can effectively reduce the corrosion rate of the bipolar plate, and the electric conductivity of the oxide layer formed on the surface after corrosion is higher than that of iron-chromium oxide formed on the surface of the stainless steel without the coating layer.